Evidence for Gas from a Disintegrating Extrasolar Asteroid

TL;DR

This study presents spectroscopic evidence of gas and heavy elements from a disintegrating asteroid orbiting white dwarf WD 1145+017, revealing active disintegration and accretion processes.

Contribution

First detection of circumstellar gas streams and detailed elemental pollution in a white dwarf caused by an orbiting disintegrating asteroid.

Findings

Detection of broad circumstellar absorption lines from multiple elements.

Pollution of white dwarf atmosphere with 11 heavy elements.

Observation of active disintegration and accretion of an extrasolar asteroid.

Abstract

We report high-resolution spectroscopic observations of WD 1145+017 -- a white dwarf that recently has been found to be transitted by multiple asteroid-sized objects within its tidal radius. We have discovered numerous circumstellar absorption lines with linewidths of $\sim$ 300 km s$^{-1}$ from Mg, Ca, Ti, Cr, Mn, Fe and Ni, possibly from several gas streams produced by collisions among the actively disintegrating objects. The atmosphere of WD 1145+017 is polluted with 11 heavy elements, including O, Mg, Al, Si, Ca, Ti, V:, Cr, Mn, Fe and Ni. Evidently, we are witnessing the active disintegration and subsequent accretion of an extrasolar asteroid.